Measuring instrument.



E. H. BRISTOL.

MEASURING INSTRUMENT.

APPLICATION FILED NOV. 9. 1914.

1,290,890. Patented Jan. 14,1919.

.E'd arHBzzaks 202.

L I! f %a detac v UNITED STATES PATENT OFFICE.

EDGAR H. BRISTOL, OF I'OZBOBO,

MASSACHUSETTS, ASSIGNOB TO THE FOXBOBO COH- PAII'Y, 01' 3013030, MASSACHUSETTS, .A CORPORATION OF MASSACHUSETTS.

MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented Jan. 14,1919.

Application fled November 0, 1914. Serial Io. 870,882.

To all whom it may concern Be it known that I, Enean H. BRISTOL, a citizen of the United States, and a rgsident of Foxboro, Massachusetts. have invented an Improvement in Measuring Instruments, of which the following description, in connection with the accompanying drawin is a specification like chara ters on the awings representlng like parts. (f

This invention relates to measuri g and recording instruments, and among other ob- 'ects J ably clamping a recording chart to a shaft; an adjustin device for causing the index to s in line with radial graduations on the o rt; and a device for lifting the index out of engagement with the chart and adapted automatically to be released from the index on the closing of the cover of the casing containing the chart.

he character ofthe invention ma be best understood by reference to the following description of an illustrative embodiment thereof shown in the accompanying drawing, wherein:

Figure 1 is a front elevation of an illus trative instrument shown herein as embodying the invention equipped with the chart clampin device. the index adjusting device and the index lifting device;

Fig. 2 on an enlarged scale is a plan of the index adjusting device;

Fig. 3 is a side elevation of the device shown in Fig. 2 looking toward the left of said figure;

Fig. 4 on an enlarged index lifting device;

Fig. 5 is a side elevation of the device shown in Fig. 4 showing its cooperation with the cover of the casing;

Fig. 6 on an enlarged scale is a side elevation of a part of the chart clampin device;

Fig. 7 is a side elevation of t e chart clamping device;

Fig. 8 is a vertical section taken on line 8-8 of Fig. 7; Fig. 9 is a view part1 in side elevation and partly in section 02 the clamping device 5 and Fig. 10 is a transverse section taken on line 10-10 of Fi 8.

Referring to t e drawing, 1 designates a. casing for receiving the instrument provided with a cover 3 hinged thereon as at 5 and scale is a plan of the 1provides an improvement in means for dIVlSlOIlS of time and circular concentric graduations for representing divisions of pressure or other condition desired to be recorded. The chart may be slid freely beneath tabs 17 projecting from said plate 9. o rotate the chart on the plate a shaft 19 1s provided within the casing adapted to be driven by a time train unnecessary to show herein. To secure the chart to this shaft a clamping device is provided comprising two clamping members 21 and 23 having opposed clamping faces which abut respectively against the front and back surfaces of the chart. The member 21 is provided with a boss 25 projectingthrough a central perforation 27 in the chart and into a recess 29 provided in the member 23 and extending into the latter from the clamping face thereof. This boss is provided with a slightly tapered portion 31 which enters the perforation in the chart and accurately centore the latter. The member 23 is secured to the shaft 19 in any suitable manner, herein by providing said shaft with a reduced end 33 having a shoulder 35 against which said member is seated. A look screw 37 is threaded into a bore in said reduced end 33 to prevent rotation of the member 23 thereon. It will be observed that the member 23 has no Fart whatever projecting through the or oration in the chart. When the memr 21 is removed the front end or clamping face of the member 23 lies substantiall in the same plane'as the front face of the 0 art supporting plate 9 or, in other words is flush therewith. This makes it possible to slide the chart into position across the face of said plate beneath the recording index, to be reiferred to, without materially disturbing the after.

The members 21 and 23 are provided with suitable yielding means carried by one of them interengagmg with the other to clamp the chart between the opposed clamping faces of the two members. As shown herein this means comprises one or more balls or normally urged toward said depressions by suitable yiel ing means typified herein as a helical band-like spring 45 having its ends hooked together as at 47 (Fig. 10). This spring engages all three of the balls 39 and is locatedin a circumferential groove 49 in the member 23, which groove serves to prevent the spring from slippin up or down on the latter. Herein the epressions 43 are of conical form and are so placed that the balls engage the conical surfaces on the sides nearest to l he inner end of the boss 31 as will be evident by reference to Fig. 8. It will be obvious that the inward pressure of the balls on these inclined surfaces will tend to draw the member 21 inwardly with respeot tothe member 23 and accordingly the chart will be clamped between the clamping faces of the two members by spring tension.

This has the advantage of provldm for a uniform clamping action on the c art as compared with the use of a screw for this purpose.

The member 21 is provided with a knurled head 51 bymeans of which it may be readily manipulated with the fingers.

The clamping device thus far described is substantially similar to the one disclosed in Letters Patent No. 1048804 granted to me December 31, 1912. An important feature of the present invention relates to the rovision of means facilitatin the intr uction of the balls to and their removal from the depressions 43. 'To accomplish this the boss is provided with grooves or Ways 53 le tothe depremions 453. These 'rooves are mi led in the ta ered boss paralle to the surface thereof an consequently the axial lines of the grooves incline inward toward the axis of said boss. The grooves laterally communicate with said depressions leaving shoulders on said dc ressions which will be eifective to-receivet e'bearing force of the balls and resist a diredt withdrawal of the clamping member 21 in'the direction of the axis of said members.

When it is desired to clam a chart between the members the boss 0 the member the mem 21 is inserted in the recess in the member 23 with'the guide grooves 53 presented to the balls A very] sllght ressure on the member 21 toward t e mem r 23 will cause the balls to follow along said guideways and spring into said do ressions, seatin themselves ainst the s oulders 55 and ocking r 21 ainst withdrawal from the member 23. In t e course of the passa of the balls along said guideways there wil of course be a slight 'rotative movement imparted to the member 21. There is therefore a shght screwing of one member into the other, but when the balls are seated against these de ressions there is no screwi action, but out e contrary one member is yieldingly drawn into the other securely to clamp or E2? the chart to the time train driven shaft. s ressure is always the same. Conseuent y successive charts are clamped to the s aft with equal force.

When it is desired to separate the members to permit the removal of the chart the member 21 is given a slight pull outward away from the member 23 accompanied balsa slig t rotative movement. T1118 will locate the balls from the shoulders of the 110-175 pressions and permit them to freely follow out through the obli ue 'deways.

These guideways cilltate which the clamp' members may be assembled and separate and eatl reduce the wear on the parts and pro ong t e life of the device. The facilitate the passage of the balls to and tom the depressions without in any way decreasing the effectiveness of the locking enga ent of the balls with the depressions. he inward inclination of the grooves enables the balls to be gradually pressed outward in their pockets until they reach the depressions, whereupon they jump therein.

Next will be described the device for adjustin \the index so that the pen point thereof wil swing radially across the chart parallel to the radial graduation chart and insure an accurate record. In Figs. 2 and 3 is shown an arm or sup ort 57 adapted to be connected to a sha (not shown) for swingin the index across the chart to register an record pressure, temperature or other condition. Said support is formed to resent a ortion 59 substantially paralle to the 0 art. On the end thereof is pivoted an index 61 preferably of resilient material carrying at its end a pen for making the record on the chart. To set the index in diiferent positions of adjustment relativel' to the arm 57, each is rovided with a ug conveniently in the arm of a bolt 63 pivoted thereon. A screw 65 is entered loosely through an eye in one of these lugs an threaded into an e e in the other and has a head 67 for limiting the shding of the index lug along the screw. A.

sprinfietiypified herein as a wire coil 69 is provl havin one end secured to said supg ilrt and the 0 er end secured to the index. is spring tends to turn the index on Its pivot and swing the index lug away from the support lug shding the former along the screw into engagement with the head 67 thereof. To adjust the index relatively to the support the screw 67 is turned, thereby causing the lugs to approach or recede from one another as d The spring causes the index to follow the head of the screw in whatever position the screw may placed Before a chart is removed from its supporting plate the index should be adjusted up away therefrom to revent its makin a line on the chart during its withdrawafi the ease with i lines on the 6 bracket.

0 one for entrance into a To accomplish this a lifting device is provided (Figs. 4 and 5) comprising a bracket 71 secured to the plate 9 by a screw 73 entered through an open ended slot 75 in said On 9. lug 77 of said bracket is a pin 78 on which is pivoted a lever 79 having an arm or finger 81 adapted to project between the index and chart and substantially radially toward the center of the latter. To facilitate the rocking of the lever about its pivot it may be formed to present a handle 83. A spring typified herein as a leaf spring 85 has one end secured to said lever and its other end reversely bent outward and back toward said lever in substantially U-shaped form. The pin 78 draws the lever a ainst the bracket lug 77 with sufficient friction to hold the lever 1n its different positions of adjustment.

In use when it is desired to remove a chart the handle 83 is pressed toward the plate 9, thereb lift'in the finger 81 away from said p ate an said finger in turn lifts the index up out of engagement with the chart. It is important after a new chart is inserted into the casing that the index pen should rest on the chart in readiness to make a record thereon. By the device described this is automatically accomplished on the closing of the cover of the casing. The cover when closing engages the spring 85' and rocks the lever 79 until limited by its engagement with the chart supporting plate, thereby causing the finger 81 thereof to move toward'the plate 9 and ermit the'index to rest on the chart. The yielding of the spring provides for lost motion between the indexsupporting end of the lever and the cover and permits a complete and secure closing of the latter.

Havingdescrihed oneillustrative embodiment of the invention without limitin the same thereto, what I claim as new and desire to secure by Letters Patent is:

1. In an instrument of the class described, the combination of opposed clamping members, one havin a projection for entrance into a recess of tie other, pockets in the wall of said recess, de ressions in said projection, balls in said poc ets, a band-like sprmg for pressing said balls toward said depressions, and grooves oblique to the axis of said projection for guiding the balls into said depressions.

it a 2. In an instrument of the class described,

e combination of opposed clampin members for receiving a record sheet etween them, and means to secure said members together including a spring pressed hall on depression on the other and a groove oblique to the axis of said members for guiding said ball to said depression.

3. In an instrument of the class described,

6 the combination of opposed clamping mem- -the combination of a bracket, an arm hers for gripping a record sheet between them, andmcans detachahly to secure said members together includin spring pressed rounded elements on one or entrance into depressions on the other and grooves oblique to the axis of said members for guiding said roundedelements into said depressions.

4. In an instrument of the class described, the combination of opposed clamping members for ipping a record sheet between them, an means for detachably securing said members together including rounded elements in one and depressions in the other for receiving said rounded elements and resenting shoulders for resistin direct axial separation of said members and guideways for conducting said rounded elements into locking engagement with said shoulders.

5. In an instrument of the class described, the combination of a support, an index pivoted thereon, lugs pivotally connected to said index and support, a screw loose in an eye in one of said lugs and threaded into an eye of the other, a head on said screw, and a spring connected to said index and support tending to slide one of said lugs along the screw against said head.

6. In an instrument of the class described, the combination ofa support, an index pivoted thereon, index in different positions of pivotal adjustment relative to said support including,

spring means tending to rotate said index about its pivot, a fix ed rotatable member, and an adjustable screw pivoted on the index and connecting it with said member for resisting the rotation of said index, the screw being slidahly engaged with one of the connected elements and threaded into the other.

7. In an instrument of the class described, the combination of a support, an index pivoted thereon, and means for holding said index in different fixed positions of adjustment relative to said support including a spring coil having its ends secured to said index and support the diametrical expansion of said coil tending to move said parts relatively, and a screw connected to said index and su port with provision for adjustin one re atively to the other against said sprin 8. 11 an instrument of the class described,

pivoted thereon having a finger for lifting a recording index out of engagement with a chart and spring means on said arm adapted to be engaged by the cover of the instrument to automatically rock the arm and permit the engagement of the index with the chart .on the closing of the cover.

ing movement thereto from the cover of the instrument to permit the return of the index to the chart.

10. An index liftin device comprising a bracket, a lever pivo intermediate its ends on said bracket having an arm for engagement with an index, a handle for rockm said lever, and a springconnected to sai arm for engagement with the cover of the casing.

11. In an instrument of the class described, a casing a cover therefor, a record sheet support and an index adapted to move over a record sheet associated with said casing, and means for liftingv the index out of engagement with the record sheet com rising a lever pivoted to said casing and aving an arm or engagement with the index, a portion of said lever bein disposed in the path of the cover whereby t e closing of the cover will actuate the lever to permit the return of the index to the record sheet.

12. In an instrument of the class de scribed, a casing, a cover therefor, a record sheet support and an index adapted to move over a record sheet associated with said casing, and means for lifting the index out of engagement with the record sheet com rising a lever pivoted to said casing and aving an arm for engagement with the index, said lever presenting a lost motion device in the path of said cover through which the closing of the cover actuates the lever to plermit the return of the index to the record 5 eet.

13. In an instrument of the class described a casing having a dial to support a circular chart and an index pivoted to swin toward and from the center of the dial, sai index normally engaging the chart, a door for the casing to cover the dial and means independent of said door whereby the index may be lifted from the dial when the door is open, said means adapted to be enga ed by said door in its closin movement or lowering the index toward t e dial when the door is shut.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

EDGAR H. BRISTOL.

Witnesses: r

HENRY T. Wmnmms, Roam H. Kxmmn. 

